Commands for getting information about the system and user activity

date – display the current date and time

cal – display the calendar for the current month

uptime – show the time since the last OS boot.

w – information about users who have registered in the system

users - a list of the names of users logged in to the system.

last is the list of users logged in according to the data from the special file /var/log/wtmp. The name, terminal, login time, IP address, etc.

last-ad – information about users logged in, with the name of the computer from which the login was performed displayed in the last column.

last –F - display the user login time, session duration, and logout time.

last –x - display information about shutdowns, reboots, and system startup level changes.

last root - display information about the root user's sessions.

last -n 10 user1 - display information about the last ten sessions of the user user1.

lastlog - display a list of all users and the time of their last login.

whoami is the name under which you are currently working in the system.

finger user – show information about user

uname -a – display all information about the system.

uname -vr – display the operating system release number and kernel version.

df – display information about disk usage.

du – display information about the use of the current directory

free – information about the use of real and virtual memory.

whatis app - Display brief information about the app from the documentation database.

whereis app – where the executable app module is located

which app – which executable module of the app application will be launched by default.

man command – display the reference information for the command command